Roof Pitch Calculator

Rise / run • x:12 • θ°

📈 Rise

Tip: leave empty if you want to solve for rise.

📏 Run length

Tip: leave empty if you want to solve for run.

🪚 Rafter length

Computed from Pythagoras: rafter² = rise² + run².

⦿ Roof pitch (°)

θ = arctan(rise/run).

％ Roof pitch (%)

Percent = 100 × (rise/run).

🔢 Roof pitch (x:12)

Common US format: rise per 12 units of run (e.g., 4:12).

⚡ Quick Summary

Enter any two compatible values (e.g., rise & run, or angle & run) and the rest will update automatically.

📚 References

Topic	Key formula / note	Source
Roof slope formats	Angle (°), percent, and x:12 ratio	Wikipedia – Roof pitch
Right triangle relation	rafter² = rise² + run²	Standard geometry / trigonometry text

More of our calculators...

Elevation Grade Calculator

Free elevation grade calculator. Enter rise and run to get slope ratio, percent grade, and angle of elevation in degrees or radians. Fast, accurate, and easy to use.

Square Footage Calculator

Free square footage calculator: enter length and width (ft/in/m) to get area in ft² and m². Add multiple rooms and switch units instantly.

Tank Volume Calculator

Tank volume calculator for cylindrical, rectangular & oval (horizontal/vertical) tanks. Enter dimensions & fill % to get capacity in gallons, liters, m³.

Taper Calculator

Free taper calculator: enter small/large diameters and length to get taper per inch (TPI), taper per foot (TPF), taper ratio, and angle. Supports metric/imperial; shows formulas, steps & PDF.

Sand Calculator

Free sand calculator: enter area & depth to get volume (yd³/m³), tons, bags, and cost. Density presets (dry/damp), rectangles/circles, coverage; instant steps & PDF.

Ramp Calculator

Free ramp calculator: enter rise and desired slope to get ramp length, run, angle, and grade. ADA presets (1:12, 1:20) & custom limits. Supports ft/m; instant steps & PDF.

Pipe Volume Calculator

Calculate pipe volume from inner diameter and length. Get capacity in m³, liters, and US gallons (plus per-length). Supports mm/in and ft/m. Shows formula and steps; instant results & PDF.

Gravel Calculator

Free gravel calculator: enter area & depth to get volume (yd³/m³), tons, bags, and cost. Supports rectangles, circles, driveways; density presets; instant steps & PDF.

Framing Calculator

Free wall framing calculator: enter wall length/height, stud spacing (16″/24″ o.c.) & openings to get studs, plates, headers, sheathing and cost. Metric/imperial with waste %, steps & PDF.